The invention concerns an electrical cable for an appliance, such an appliance as well as a method for producing the electrical cable.
Such a cable is regularly used in various appliances, in particular for a vacuum cleaner, such as a floor vacuum cleaner, and in general for electrical appliances demanding a dynamic cable behavior. Such devices might have automatic or manual cable retrieving devices such as exemplarily described in US 2002/0008172 A1. Such a cable retrieving device often comprises a cable drum that allows the user of to store the cable inside the vacuum cleaner, thus avoiding to tangle.
Each storing or revival operation by the users stretches the electrical cable. This repeating tension can lead to various malfunctions in the cable, such as a breaking of the conductors inside the cable structure, which leads to the case where the vacuum cleaner does not receive electrical power and stops working. Also various insulation layers or sheathing layers of the cable can break. Depending on the broken layer, this can lead to short circuits between the conductors or even to potential hazardous situations for the user, if a conductor is not shielded to the outside of the cable. Therefore cables must be able to remain functional even after a high number of bending or flexing cycles in order to be used for vacuum cleaners. Further to this requirement, the variance of the maximum number of jerking or flexing cycles before breakdown of such an electrical cable should be low.
Additionally, cables used for vacuum cleaners should be able to handle multiple cable jerks and should have a high resistance to sharp object impacting the outer sheath, before a breakage of the center conductors of such a cable occurs. Prior art cables regularly suffer breakdown of the center conductor at around 500 cycles in the jerk test and around 150,000 cycles in the flexing test.